Star Trek: Peaceful Occupations
Civilian Scot's Vulcan
One of the first members of Sirco cell was a Vulcan pilot named Solek, apparently a recent migrant to Salva II, who helped steal the Hur’Un. A few weeks later, he transferred to Villegas cell, and served as the helm officer of the Guevara for over two years.
It only later emerged that he had been a Romulan infiltrator all along, with ample access to Maquis operational secrets. A cloaked Romulan scout ship extracted him in the Delta 110 system, along with a number of vital computer records.